Electromagnetically driven selfregulating fluid compressor for use in refrigerating machines



y 29, 1952 JEAN-LEON REUTTER 2,605,042

EILECTROMAGNETICALLY DRIVEN SELF-REGULATING FLUID COMPRESSOR FOR USE IN REFRIGERATING MACHINES Filed July 15, 1 947 23 Eggs m g a m 26 24 E 1 E [191 EM.

fm/enf Patented July 29, 1952 ELECTROMAGNETICALLY DRIVEN SELF- REGULATING FLUID COMPRESSOR FOR USE IN REFRIGERATING MACHINES- Jean-Leon Reutter, Geneva, Switzerland Application July 15, 1947, Serial No. 761,080 In Switzerland July 26, 1946 2 Claims.

My invention relates to fluid compressors and more particularly to electro-magnetically driven self-regulating fluid compressors for use in refrigcrating machines.

An important feature of the invention resides in the provision of a unit comprising the movable part of the compressor and an armature controlling said movable part, the mass of said unit being subjected to the action of such a spring that the natural oscillating frequency of said unit when running idle be lower than that imparted thereto by the periodic feeding current and equal to the latter when the necessary power for producing a certain rate of compression is added to the power of the spring.

The advantage of this arrangement resides in that the stroke of the movable part of the compressor (for instance the piston), automatically increases with the rate of compression.

In the machine described heretofore, the natural frequency of the unit comprising the weights and th spring is regulated so as to be in resonance with the frequency of the feeding current. When the machine runs idle, th amplitude tends to assume an excessive value, and various means have been described for avoiding this inconvenience. Furthermore, various processes have been described for regulating the power while running.

It is an object of my present invention to automatically attain those results in the simplest way.

The strain of the compression produces in the oscillating movement of the system mass-elastic power not only a damping effect which would lower their own frequency, but also a power which, in the second half of the compression, will be added to that of the resilient blade, and which consequently increases the natural frequency of the system. This fact is in accordance with the fundamental theory of harmonic oscillations whose differential equation is dzi K X where the frequency increases with K.

In order to use this property according to my invention, the natural frequency of the weights and of the spring power is regulated in such a way that the natural frequency of th system be substantially lower than that which is imparted thereto by the driving current. When idle running, for instance at the beginning of the operation, the amplitude is small becaus of the frequencies being out of phase, but it increases according as the rate of compression is raised, and

finally will reach to the resonance and consequently to the maximum of amplitude and power for the maximum foreseen rate of compression.

In the refrigerating machines, the following result is obtained:

When the ambient temperature is comparatively low (15 C. for instance) the pressure within the condenser is low, the rate of compression is small and so is consequently the amplitude, thus realizing saving of feeding current and of wear of the apparatus. According to the ambient temperature rising, the rate of compression increases and so does the amplitude and the mass is dimensioned in such a way that the maximum amplitude occurs at the maximum foreseen ambient temperature. The construction shown herein has for its object to create throughout the coils a reversal of the direction of the induction flux produced by the magnets, thus obtaining an induced electromotive force as high as possible. To this end there are provided two resilient blades each of which carries two permanent magnets whose magnetic axes are parallel and opposite in direction and which successively penetrate at each half-period into the magnetic circuit.

The accompanying drawings represent, by way of examples, one embodiment of the invention.

Fig. 1 is an elevational view of an electromagnetically driven gas compressor taken from a plane, the trace of which is the line I-I on Fig. 3, and including an axial section of the cylinder of said compressor.

Fig. 2 is a side elevational view thereof.

Fig. 3 is a horizontal section thereof, being taken on line III-III of Fig. 1.

The gas compressor shown in the Figures 1 to 3 comprises a base plate II to which are secured two resilient blades 2| and two brackets I carrying the laminated field frame of an inducing field magnet 24. To the top of these brackets is fastened a compressor cylinder 8 containing two pistons 3 symmetric-ally connected each of them by a flexible rod 4 with one of the resilient blades 2|. At its median portion, the cylinder 8 is provided with a suction valve 9 and a delivery valve I0. The weights I2 are calibrated in such a way that the natural period of oscillation of the blades 2|, together with the corresponding weights l2 and pistons 3, be lower than that which is imparted thereto by the inducing field magnet 24.

The field magnet 24 comprises two parallel and opposite portions I5, l6, each of which is cut by an air-gap with polar faces ll, [8, I9, 20, respectively, substantially at right angles to the main direction of the flux through the said airgaps. Each of the resilient blades or leaf-springs carries two permanent magnets 22 and 23 whose axes of magnetization are parallel to one another but opposite in direction. Thesemagnets 2223 and the corresponding leaf-springs 2| are adapted to oscillate in the air-gaps in a direction parallel to the polar faces I1, l8 and I9, 20.

The inducing field magnet 2| is energised by alternating current of predetermined frequency flowing through the coils 25 and 26, so that both the magnets 22 simultaneously penetrate into the.

air-gaps of the inducing field magnet at a given half period. In the subsequent half period, both the magnets 23 penetrate simultaneously thereinto. As the magnetic axes of these magnets are opposite in direction, the flux will be reversed throughout the coils thus producing a high induced electro-motive force and substantially increasing the power and the efficiency of the compressor.

A further advantage of this construction resides in that the magnets are always solicited in the very direction where the flux produced by the coils tends to increase the flux which passes through them, that is to increase their magnetization. The demagnetization by accidental excess of intensity within the field-magnets will, thus be made impossible.

What I claim is:

1. In an electro-magnetically driven fiuid compressor, the combination of aframe, an inducing field magnet secured to said frame and having two parallel and opposite portions, each of which is cut by an air-gap with polar faces substantially at right angle with the main direction of the flux; said field-magnet being energizable by alternating current of predetermined frequency; a pair of leaf-springs secured to said frame by one of their ends, each leaf-spring being adapted to oscillate in a corresponding air-gap, in a direction substantially parallel to said polar faces; a pair of permanent magnets carried by each leafspring, said permanent magnets having their magnetic axes parallel to the flux in the corresponding air-gap, but opposite in direction with respect to each other; a compressor cylinder for gaseous fluid secured to the frame, two spaced pistons reciprocally mounted in said cylinder and symmetrically connected to one of the said leafsprings; a suction pipe and a delivery pipe communicating with the middle part of the cylinder between the two pistons, the weights and sizes of the movable unit constituted by the leafsprings with permanent magnets, pistons and their connections, being determined in such a manner that the natural frequency of oscillation of said unit, by no delivery pressure in the cylinder, be less than that of the alternating current, said natural frequency increasing when the rate of compression increases so as to become almost equal to the frequency of the alternating current.

2. An electro-magnetic reciprocating motor comprising in combination: a frame, an inducing field-magnet secured to said frame and having two parallel and opposite portions, each of which is cut by an air-gap with polar faces substantially at right angle with the main direction of the flux; said field-magnet being energizable by alternating current of predetermined frequency; a pair of leaf-springs secured to said frame by one of their ends, each leaf-spring being adapted to oscillate in a corresponding airgap, in a direction substantially parallel to said polar faces; a pair of permanent magnets carried by each leaf -spring, said permanent magnets having their magnetic axes parallel to the flux in the corresponding air-gap, but opposite in direction with respect to each other; the relative arrangement of the permanent magnets in the air-gaps and the flux in the latter being such that at a given half period 01' the alternating current, two of the permanent magnets are simultaneously attracted to the centre of said air-gaps, and the other two magnets, pushed away from said air-gaps, these motions being reversed at the next half-period; means for adjusting the natural frequency of oscillation of the movable unit constituted by the leaf-springs with their permanent magnets.

JEAN-LEON REUITER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 202,764 Smyth Apr. 23, 1878 1,333,298 Evershed Mar. 9, 1920 1,689,419 Bronander Oct. 30, 1928 1,978,866 Konig Oct. 30, 1934 2,169,827 Whitted Aug. 15, 1939 2,240,307 List Apr. 29, 1941 2,245,391 Dickten June 10, 1941 2,245,981 Knopp June 17, 1941 2,259,131 Fleischer Oct. 14, 1941 2,280,610 Young Apr. 21, 1942 2,429,441 Williams Oct. 21, 1947 2,430,151 Whitted Nov. 4, 1947 FOREIGN PATENTS Number Country Date 130,078 Austria Oct. 25, 1932 496,049 France July 21, 1919 

